2011 75hp 4 stroke EFI bogs down

[fisics67]

Engine starts easily, sounds and runs really smooth. But after about a minute at half to full throttle it will bog down and sometimes stall out. After a few seconds it will usually pick back up and run fine again for a bit. Sometimes it repeats this again, other times it will run fine until you stop and start again. Feels like a fuel problem. Filters have been changed, so have the plugs, oil, air filter... I bypassed the onboard fuel tank, thinking it might be a clogged fuel pick-up, but no change. Obviously both fuel pumps work, at least most of the time. I'm starting to wonder if there isn't an intermittent problem with the float switch inside the FSM. Since it is intermittent though, I am not sure if the problem would be evident if I removed it and tested it, and they are expensive to change just on a hunch.

Any thoughts/input would be appreciated. Thanks!

 

[RideNFishCA]

A buddy of mine had his Merc 4 stroke do the same type of thing. Would run wide open but it was very random on when it would bog down and sometimes quit. Left us stranded once. He replaced a bunch of stuff but in the end they found a piece of plastic or similar that was circulating in the fuel pump and would block the passage. That is why it was random. I think it was something from the pump. It couldn't have passed through any fuel filter.

Just a thought...

 

[fisics67]

A buddy of mine had his Merc 4 stroke do the same type of thing. Would run wide open but it was very random on when it would bog down and sometimes quit. Left us stranded once. He replaced a bunch of stuff but in the end they found a piece of plastic or similar that was circulating in the fuel pump and would block the passage. That is why it was random. I think it was something from the pump. It couldn't have passed through any fuel filter.

Just a thought...

Thanks for the reply! You help confirm my decision to pull apart the FSM.

I have taken apart my Fuel Supply Module and found that I cannot get any continuity through the electric float switch that runs the lift pump. I am not sure how it worked at all actually.

Once I get a new switch and try it out, I will update this.